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862. KATP channels are involved in regulatory volume decrease in rat cardiac myocytes
- Creator:
- Leiyu Shi, Xu, M., Liu, J., Zhang, Z., Bao, Z., Wang, Y., Wang, C., and Wang, Jun
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, whole-cell patch clamp, ATP-sensitive K+ channel, regulatory volume decrease, 14, and 612
- Language:
- English
- Description:
- Regulatory volume decrease (RVD) is essential for the survival of animal cells. The aim of this study was to observe the RVD process in rat ventricular myocytes, and to determine if the KATP channels are involved in the RVD process in these cells. By using reverse transcriptase polymerase chain reaction and Western blot analysis, we demonstrated that there are two types of KATP channels expressed in rat ventricular myocytes: Kir6.1 and Kir6.2. When rat cardiac myocytes were exposed to hypotonic solution, cell volume increased significantly within 15 min and then gradually recovered. This typical RVD process could be inhibited by a Cl– channel blocker (0.5 mM 9-anthracene-carboxylic acid , 9-AC), a K+ channel blocker (5.0 mM CsCl) and a KATP channel blocker glibenclamide (10 μM). Electrophysiological results showed that hypotonic solution activated a whole-cell current, which had similar biophysical characteristics with KATP opener (pinacidil)-induced currents. This current could be blocked by glibenclamide. Our data suggested that the RVD process in rat ventricular myocytes is dependent on the activation of K+ channels, and that KATP channels are involved in this process., L. Shi ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
863. Kinetics of cardiac RyR channel gating studied at high temporal resolution
- Creator:
- Miroslav Dura, Ivan Zahradník, and Zahradníková, A.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, kinetika, kinetics, ryanodine receptor, gating, calcium release, cardiac muscle, 14, and 612
- Language:
- English
- Description:
- Measurements of ryanodine receptor (RyR) activity during dynamic changes of calcium concentration have suggested that RyR has at least four calcium binding sites, and that activation transpires as an increase in the activity within the high open probability H-mode. Binding of several Ca2+ ions within the H-mode should manifest itself in the steady-state RyR activity by the presence of multiple closed times. However, previously only two closed times were detected in the H-mode of RyR activity. Here we recorded steady-state activity of single cardiac RyRs with high temporal resolution and compared it to data simulated under the same conditions using our previously published model of RyR gating. At a 10 kHz resolution, the closed time histograms of both experimental and simulated data had three exponential components. The closed times of simulated data were not significantly different from those obtained experimentally. After filtering at 2 kHz, only two exponential closed time components with time constants not significantly different from those previously published could be detected in both experimental and simulated records. The conformity of the steady-state experimental data to the model derived from the dynamic data provides further support for the idea that RyRs need binding of multiple Ca2+ ions to open., M. Dura, I. Zahradník, A. Zahradníková., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
864. Kynurenic acid prevented social recognition deficits induced by MK-801 in rats
- Creator:
- Zdeněk Hliňák and Ivan Krejčí
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, amnesia, kynurenic acid, MK-801, social recognition, working memory, 14, and 612
- Language:
- English
- Description:
- MK-801 impaired social recognition potency of adult male rats when given immediately after the initial interaction with a juvenile rat. Administration of kynurenic acid prior to the initial interaction protected the adults against recognition deficits induced by MK-801. When re-exposed at a delay of 30 min to the familiar juvenile, social investigation in the adults was significantly reduced. Thus, the adults are able to remember olfactory stimuli emitted by juvenile con-specifics., Z. Hliňák, I. Krejčí., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
865. L-arginine in combination with sildenafil potentiates the attenuation of hypoxic pulmonary hypertension in rats
- Creator:
- Hikmet Al-Hiti, Martin Chovanec, Vojtěch Melenovský, Olga Vajnerová, Alena Baňasová, Josef Kautzner, and Jan Herget
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, plicní hypertenze, pulmonary hypertension, chronic hypoxia, l-arginine, sildenafil, 14, and 612
- Language:
- English
- Description:
- Chronic hypoxia induces an increased production of nitric oxide (NO) in pulmonary prealveolar arterioles. Bioavailability of the NO in the pulmonary vessels correlates with concentration of L-arginine as well as ac tivity of phosphodiesterase-5 enzyme (PDE- 5). We tested a hypothesis whet her a combination of L-arginine and PDE-5 inhibitor sildenafil has an additive effect in reduction of the hypoxic pulmonary hypertension (HPH) in rats. Animals were exposed to chronic normobaric hypoxia for 3 weeks. In the AH group, rats were administered L-arginine during chronic hypoxic exposure. In the SH group, rats were administered sildenafil during chronic hypoxic exposure. In the SAH group, rats were treated by the combination of L-arginine as well as sildenafil during exposure to chronic hypoxia. Mean PAP, structural remodeling of peripheral pu lmonary arterioles (%DL) and RV/LV+S ratio was significantl y decreased in the SAH group compared to hypoxic controls even decreased compared to the AH and the SH groups in first two measured parameters. Plasmatic concentration of cGMP and NOx were significantly lower in the SAH group compared to hypoxic controls. We demonstrate that NO synthase substrate L-arginine and phosphodiesterase-5 inhibitor sildenafil administered in combination are more potent in attenuation of the HPH compared to a treatment by substances given alone., H. Al-Hiti ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
866. L-malate enhances the gene expression of carried proteins and antioxidant enzymes in liver of aged rats
- Creator:
- Zeng, X., Wu, J., Wu, Q., and Zhang, J.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, physiology, l-malate, mitochondria antioxidant, malate-aspartate shuttle, real-time reverse transcription polymerase chain reaction (real-time RT-PCR), 14, and 612
- Language:
- English
- Description:
- Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. To investigate the antioxidant mechanism of L-malate in the mitochondria, we analyzed the change in gene expression of two malate-aspartate shuttle (MAS)-related carried proteins (A GC, aspartate/glutamate carrier and OMC, oxoglutarate/malate carrier) in the inner mitochondrial membrane, and three antioxidant enzymes (CAT, SOD, and GSH-Px) in the mitochondria. The changes in gene expression of these proteins and enzymes were examined by real-time RT-PCR in the heart and liver of aged rats treated with L-malate. L-malate was orally administered in rats continuously for 30 days using a feeding atraumatic needle. We found that the gene expression of OMC and GSH-Px mRNA in the liver increased by 39 % and 38 %, respectively, in the 0.630 g/kg L-malate treatment group than that in the control group. The expression levels of SOD mRNA in the liver increased by 39 %, 56 %, and 78 % in the 0.105, 0.210, and 0.630 g/kg L-malate treatment groups, respectively. No diffe rence were observed in the expression levels of AGC, OMC, CAT, SOD, and GSH-Px mRNAs in the heart of rats between the L-malate treatment and control groups. These results predicted that L-malate may increase the antioxidant capacity of mitochondr ia by enhancing the expression of mRNAs involved in the MAS and the antioxidant enzymes., X: Zeng, J. Wu, Q. Wu, J. Zhang., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
867. Lactate dehydrogenase activity in human placenta following exposure to environmental pollutants
- Creator:
- Kaiglová, A., Eva Reichrtová, Adamčáková, A., and Wsólová, L.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, placenta, human placenta, lactate dehydrogenase, environmental pollutants, 14, and 612
- Language:
- English
- Description:
- The impact of environmental pollution at the place of residence of pregnant women and of their smoking habits on the cellular energy metabolism of placental tissue was investigated. Samples of full-term placentas were randomly collected from two environmentally different regions of Slovakia (Bratislava, Stará Ľubovňa) and the activity of lactate dehydrogenase (LDH) was measured. Our results showed enhanced LDH activity in the placenta that was dependent on both the type of environmental pollutants at the place of residence and the smoking habits during pregnancy. The enhanced LDH activity may reflect hypoxic conditions due to the accumulation of heavy metals and toxic compounds of tobacco smoke in the placental tissue. A high content of heavy metal particles, found in placental samples from Stará Ľubovňa in our previous studies, might contribute to the increased LDH activity in placentas from this region. We hypothesize that fine metal particles deposited in the placental tissue might be phagocytozed by the syncytiotrophoblast, thus contributing to the decreased oxygen level in placental tissue., A. Kaiglová, E. Reichrtová, A. Adamčáková, L. Wsólová., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
868. Late blood pressure reduction in SHR subjected to transient captopril treatment in youth: possible mechanisms
- Creator:
- Josef Zicha, Zdena Dobešová, and Jiří Kuneš
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie, genetika živočichů, hypertenze, physiology, animal genetics, hypertension, genetic hypertension, late effects of early treatment, captopril, nifedipine, 14, and 612
- Language:
- English
- Description:
- Spontaneously hypertensive rats (SHR) are characterized by enhanced nifedipine-sensitive component of sympathetic vasoconstriction. Our study tried to elucidate the mechanisms responsible for long-term reduction of blood pressure (BP) in SHR subjected to early transient captopril treatment. Adult untreated SHR aged 30-34 weeks were compared with animals subjected to chronic captopril treatment for 6 weeks either in youth (between 4 and 10 weeks of age) or in adulthood (between 24 and 30 weeks of age). Antihypertensive effects of captopril were more pronounced in young than adult SHR. This was due to greater attenuation of sympathetic and nifedipine-sensitive BP components and prevention of residual BP rise in young captopril-treated SHR in which the reductions of nifedipine-sensitive BP component and residual BP persisted for 20 weeks after captopril withdrawal. The magnitude of nifedipine-sensitive component of sympathetic vasoconstriction is decisive for BP maintenance not only in untreated SHR but also in SHR during active captopril treatment by or after its withdrawal., J. Zicha, Z. Dobešová,J. Kuneš., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
869. Late divergence of target and nontarget ERPs in a visual oddball task
- Creator:
- Alena Damborská, Milan Brázdil, Ivan Rektor, Eva Janoušová, Chládek, J., and Miloslav Kukleta
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, intracerebral recording, oddball task, visual evoked potentials, mental counting, memory, 14, and 612
- Language:
- English
- Description:
- Different mental operations were expected in the late phase of intracerebral ERPs obtained in the visual oddball task with mental counting. Therefore we searched for late divergences of target and nontarget ERPs followed by components exceeding the temporal window of the P300 wave. Electrical activity from 152 brain regions of 14 epileptic patients was recorded by means of depth electrodes. Average target and nontarget records from 1800 ms long EEG periods free of epileptic activity were compared. Late divergence preceded by almost identical course of the target and nontarget ERPs was found in 16 brain regions of 6 patients. The mean latency of the divergence point was 570±93 ms after the stimulus onset. The target post-divergence section of the ERP differed from the nontarget one by opposite polarity, different latency of the components, or even different number of the components. Generators of post-divergence ERP components were found in the parahippocampal gyrus, superior, middle and inferior temporal gyri, amygdala, and fronto-orbital cortex. Finding of late divergence indicates that functional differences exist even not sooner than during the final phase of the task., A. Damborská ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
870. Late effect of early hypoxic disturbance in the rat heart: gender differences
- Creator:
- Ivan Netuka, Ondrej Szárszoi, Jan Malý, Hynek Říha, Turek, D., Ivana Ošťádalová, and Bohuslav Ošťádal
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, gender, ischemie, ischemia, perinatal hypoxia, isolated rat heart, reperfusion injury, 14, and 612
- Language:
- English
- Description:
- Perinatal hypoxemia may have serious long-term effects on the adult cardiovascular system and may lead to sex-dependent changes in cardiac tolerance to acute ischemia in adult life. The aim of the study was to answer the question whether gonadectomy of the male and female rats in the early phase of ontogenetic development affects the late effect of perinatal hypoxia. Pregnant Wistar rats were placed into a normobaric hypoxic chamber (12 % O2) 7 days before the expected date of delivery. Newborn pups were kept in the chamber with their mothers for another 5 days after birth. After hypoxic exposure all animals were kept for 3 months in room air. Some of the pups were gonadectomized right after removal from the hypoxic chamber. Ventricular arrhythmias were assessed on isolated perfused hearts. Castration did not influence arrhythmogenesis in the adult normoxic or perinatally hypoxic female hearts. Nevertheless, the number of arrhythmias was decreased in perinatally hypoxic gonadectomized males. In conclusion, we have shown that perinatal normobaric hypoxia increased cardiac tolerance to acute ischemia in adult male rats; however, it had no late effect in females. Gonadectomy did not affect arrhythmogenesis in both normoxic and hypoxic female hearts, whereas in males significantly decreased the number of arrhythmias., I. Netuka ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public